1. Field of the Invention
The present invention relates to a display apparatus for use with a liquid-crystal projector or the like, for example, and its cooling method.
2. Description of the Related Art
Heretofore, in a liquid-crystal projector apparatus in which a light from a light source is irradiated on a liquid-crystal light bulb and a light traveled through the liquid-crystal light bulb is projected by a projection lens onto a screen, thereby displaying an image, cooling methods have been devised in order to prevent the liquid-crystal light bulb and various kinds of optical assemblies from becoming a high temperature by the heat from the light source.
There is known a method of cooling the liquid-crystal light bulb and various optical assemblies by a fan to take the open air into the set of the liquid-crystal projector apparatus, for example.
However, according to this cooling method, since dusts also are taken in at the same time the open air is taken in, it is unavoidable that the liquid-crystal light bulb and various kinds of optical assemblies are smudged by dusts.
As a result, dusts shuts off or irregularly reflects light traveled through the liquid-crystal light bulb with the result that an image is affected by troubles such as smudge and blur.
For the purpose of preventing the liquid-crystal light bulb and various kinds of optical assemblies from being smudged by the above-mentioned dusts, it is customary that a dust-removing filter is attached to an air inlet of the open air.
However, even though the dust-removing filter is attached to the air inlet, dusts that are smaller than the mesh of the filter cannot be removed so that fine dusts are accumulated in the inside of the liquid-crystal projector apparatus, thereby causing the aforementioned problem.
Further, according to this method, although a dust removing effect is not perfect, it is cumbersome for a user to frequently clean the filter.
Also, in the above-mentioned cooling method using the fan, since a fan noise is radiated to the outside of the housing of the liquid* crystal projector apparatus, such fan noise becomes an undesired noise other than sound to cause unpleasantness in a user/viewer while the liquid-crystal projector apparatus is in use.
As a cooling method other than the above-mentioned methods, there is considered such a cooling method in which an optical block including a liquid-crystal light bulb of the liquid-crystal projector apparatus is made of the closed type to circulate the air within the optical block.
However, since a volume of the air within the optical block is small, when this method is in use, a heat radiation property of the closed optical block should be increased so that the structure of the liquid-crystal projector apparatus tends to become complex.
It is an object of the present invention to provide a display apparatus and its cooling method in which optical assemblies can be prevented from being smudged by dusts entered into the apparatus so that an excellent image can be obtained and the apparatus can be cooled sufficiently.
A display apparatus according to the present invention comprises a housing having a screen provided on its front surface and a closed structure, an optical block having a closed structure coupling device for coupling the housing and the optical block in a closed fashion to thereby circulate the air.
According to the above-mentioned present invention, since the housing and the optical block, each having the closed structure, of the display apparatus are coupled by the coupling device which circulates the air, the air circulation route can be closed to prevent dust from entering into the optical block from the outside. Thus, a picture quality can be prevented from being lowered due to dusts which smudge the optical assemblies, thereby making it possible to obtain a satisfactory image.
Also, since the air is circulated into the housing and the optical block via the coupling means to cool the air, the optical block can be cooled efficiently under the condition that dusts are not entered into the optical block from the outside.
Also, since the optical block has the closed structure, the fan noise can be prevented from being emanated to the outside when the air flow generating means or the fan is disposed in the inside to circulate the air, for example.
When heat of the air heated within the optical block is radiated through the housing, by effectively utilizing the wide space of the housing, it is possible to more efficiently radiate the heated air.
According to the above-mentioned arrangement of the present invention, since the air is circulated between the housing and the optical block through the coupling means to cool the air during such circulation, the optical block can be cooled.
A display apparatus according to the present invention includes a housing having a screen provided on its front surface, an optical block, a light source, a first cooling device for cooling the light source and a second cooling device for cooling the optical block.
According to the above-mentioned arrangement of the present invention, the first cooling device and the second cooling device can be formed as different cooling device in correspondence with the light source and the optical block.
Also, since the present invention includes the first cooling device for cooling the light source and the second cooling device for cooling the optical block, the first cooling device and the second cooling device can be served as the respective different cooling means in correspondence with the light source and the optical block. Hence, there can be provided proper cooling device in correspondence with the light source and the optical block whose heat generating amounts are different considerably.
Accordingly, it is possible to improve the respective cooling efficiencies of the light source and the optical block. Further, since a freedom with which the light source and the optical block are designed increases, it is possible to provide the display apparatus having a more preferable arrangement.
A cooling method of a display apparatus according to the present invention is a cooling method of a display apparatus having a screen provided on its front surface and which includes a housing, an optical block and a light source, in which at least the optical block is arranged to have the closed structure to thereby cool the optical block by circulation of the air.
According to the present invention, the optical block is formed as the closed structure, whereby the optical block can be cooled by circulation of the air under the condition that dusts are not entered into the apparatus.
Further, a cooling method of a display apparatus according to the invention is a cooling method of a display apparatus includes a housing having a screen provided on its front surface, an optical block and a light source, wherein the light source is cooled by a first cooling device and the optical block is cooled by a second cooling device.
According to the present invention, the first cooling device and the second cooling device can be formed as different cooling device in correspondence with the light source and the optical block, respectively.